The present invention relates to an apparatus and a method for sterilising containers and in particular plastic containers. Various methods for sterilising containers are known from the prior art. So for example, it is known to apply a liquid and/or gaseous medium such as for example H2O2 to containers. Apart from that, also apparatus and methods have recently become known, wherein radiation and/or charge carriers has/have been applied to the containers for the purpose of sterilisation. In doing so, it is possible to insert a beam finger into the inside of the containers and to irradiate this container from the inside with charge carriers and in particular with electrons. These beam fingers have to be designed to be relatively delicate and/or respectively thin-walled so as to ensure on the one hand that the finger can be inserted through the mouth into the inside of the container and on the other hand to enable also the required high electron accelerations to be achieved. Further, such apparatus often include also cooling devices for cooling an exit window for the charge carriers.
As a result of the above, such sterilisation devices are very sensitive for example to contamination or aggressive cleaning agents, but in particular to shocks. In practice, therefore, breakdowns and failures often occur for example as a result of knocks against these beam fingers, in particular during cleaning or maintenance operations.